Gas discharge lamp



Oct. 13, 1959 H. GREBER 2,908,841

GAS DISCHARGE'LAMP Filed May 19, 1958 IN VENTOR.

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United States Patent O 2,908,841 GAS DISCHARGE LAMP Henry Greber, NewYork, N .Y. Application May 19, 1958, Serial No. 736,038 s Claims. V(Cl.313-204) The purpose of this is to increase the eiciency of gasdischarge lamps by applying'to them shields directing the electronsemanating from the filaments to regions close to the walls of said lampsand imparting to said electrons a velocity component perpendicular tothe longitudinal axes of said tubes. This velocity component addedgeometrically to the velocity component parallel to the longitudinalaxis causes the emanated electrons to pursue a helical path, which isessentially longer, and gives more chance for their collision with gasVmolecules than does a rectilinear path. The purpose of keeping theelectron paths near the Wall of the tube is to prevent the excessiveabsorbtion of light produced by them by the volume of gas near the axisof the tube.

Fig. 1 shows a view of the gas discharge tube incorporating thisimprovement. Fig. 2 presents an enlarged cross section 4-4 of said tube.In Fig. 3 can be seen a side elevation of the grid, whose front view isshown in Fig. 2.

In Fig. 1 transparent tube 1 contains two stems 2 and 3. Stem 2comprises lead Wires 5 and 6, connected to iilament 7, andstem 3comprises lead Wires 8 and 9 connected to filament 10. In front of saidfilament 7 is mounted grid 11 which has the form of a shield and issupported from stem 2 by means of wires 12. Similarly shield 13,supported on Wires 14, is mounted in front of filament V10. The designof shieldshaped grid 11 is shown in Fig. 2, which is the cross sectionalview 4-4 indicated in Fig. 1. It can be seen in Fig. 2 that shield 11comprises bulged hub 16 and a plurality of blades 15, which resembleblades of a fan. Fig. 3 is a side view of shield 11 and shows that hub16 is convex in direction of filament 7 and that blades 15 are inclinedtowards the longitudinal axis of the tube. Numerals 17, 18 show electronpaths. V

In operation of this gas discharge tube electrons emitted by thefilaments, at the start of the lamp, hit the shield and bring it lto anegative potential, so that it acts repulsively onV the further flow ofelectron. Therefore electrons emanating from the filament go along pathsparallel to the'4 bulge 16 and through the spaces between the blades 1S.Since these blades are slanted towards the longitudinal axis of thetube, the electrons,

following the slant of these blades receive a transversal rice componentof velocity, which geometrically added to their longitudinal velocitcauses them to pursue helical paths. Pursuing such paths the electronsare subject to a centrifugal force which pushes them towards the wall ofthe tube, so that they collide with gas molecules near said wall. Sincethe helical path is longer than the rectilinear, the electrons have alarger probability to collide with gas molecules. Were these collisionsto take place in the central regions of the tube, the produced lightwould be partly re-absorbed by the relatively thick layer of gas inthese regions. This cannot take place when collisions occur near thewall of the tube.

This improvement can be applied to uorescent, mercury sodium, and otherkinds of gas discharge lamps, such as neonsign lamps, and glow lamps. Itis to be understood that the here described lamp is only illustrative,and many variations and modiiications of it can be made within the scopeof the following claims.

I claim:

1. A gas discharge lamp having at least one cathode enclosed in a gaslled, insulating and transparent envelope, with at least one lead wirepassing said envelope and connecting said cathode with a source ofelectrical energy, also having a metallic shield mounted in front ofsaid cathode and provided with blades slanted in respect to thelongtiudinal axis of said tube, said shield serving for directingelectrons emanating from said cathode towards the Iwall of the envelopeand for imparting to said electrons a rotatary motion around thelongitudinal axis of the lamp.

2. A gas discharge lamp having: two filaments e11- closed in a gas lled,insulating and transparent envelope with lead wires passing saidenvelope and connecting said filament to a source of electric energy,vmetallic shields mounted in front of said filaments and provided withblades slanted towards the longitudinal axis of said lamp, said shieldsserving for directing electrons emanating from said filament towards thewall of the envelope and imparting to said electrons a rotatory motionaround the longitudinal axis of said tube.

3. A gas discharge lamp having: two laments enclosed in a gas filled,insulating and transparent envelope with lead wires passing saidenvelope and connecting said filament to a source of electric energy, ashield made of glass mounted in front of at least one of said filamentsand provided with blades slanted towards the longitudinal axis of saidlamp, said shield servingvfor directing electrons emanating from saidfilament towards the wall of the envelope and imparting to saidelectrons a rotary motion around the longitudinal axis of said tube. l

References Cited in the file of this patent UNITED STATES PATENTS

